INDUSTRIAL ASSEMBLY AND MAINTENANCE

Transcription

1 INDUSTRIAL ASSEMBLY AND MAINTENANCE LUBRICATION SOLUTIONS FOR THREADED CONNECTIONS Molykote Anti-Seize Pastes and Anti-Friction Coatings from Dow Corning

2 MOLYKOTE LUBRICANTS More than 60 years of trust, around the globe. For over half a century, OEM designers, maintenance and materials engineers around the world have trusted the Molykote brand for performance and expertise to prevent or solve many diverse lubrication problems. Formulated for extreme loads and environments, Molykote lubricants are also ideal for normal service lubrication. They deliver extended benefits as compared to conventional lubricants, such as: Long component life Extended lubricant durability Long maintenance intervals Savings of time and money With technical centers all over the world, our expanded product choices can reach you wherever you are to provide Smart Lubrication.

3 Harsh environments, heavy loads and extreme speeds can challenge your productivity. Molykote brand Anti-Seize Pastes and Anti-Friction Coatings (AFCs) help keep your equipment and processes moving smoothly. IMPROVE PERFORMANCE OF THREADED CONNECTIONS Threaded connections offer several advantages, including, but not limited to, convenient disassembly, repeated use of a fastener and accurate reassembly. However, without proper lubrication, those advantages can be lost, giving rise to significant equipment challenges and reliability concerns. BY PREVENTING: Inconsistent coefficients of friction, resulting in inconsistent bolt tension Stick-slip Stress corrosion cracking Fretting Galling Seizing Molykote brand lubricants can help your threaded connections perform well in service, from initial assembly through repeated disassemblies. They are specially formulated to withstand harsh conditions, perform in a wide range of service temperatures and resist the effects of heavy loads, salt-spray or other contaminants.

4 THE BENEFITS OF PROPER LUBRICATION Lubricants serve to reduce friction and wear, protect against corrosion and dissipate heat. The use of carefully selected lubricants can help circumvent some of the common failure mechanisms associated with threaded connections. Some key functions of proper lubrication are: Providing a consistent coefficient of friction (µ) On mating surfaces, this enables designers and applicators to minimize the complexity of obtaining proper connector preload forces and torque specifications Limits the effects of temperature and load variations, reducing fatigue failure rates Forming barriers between substrates and oxygen gas layer Prevents undesirable scale formation on thread surfaces Providing protective layers to mating surfaces Reduces the effects of oxide layer depletion, reducing the occurrence of fretting, galling, seizing and shearing Decreases exposure to corrosive, hydrogen-rich and low-melting metal environments, reducing stress corrosion cracking as well as hydrogen and solder embrittlement MOLYKOTE ANTI-SEIZE PASTES PROVIDE CONSISTENT COEFFICIENT OF FRICTION PRODUCT NAME µ t µ c K* MOLYKOTE G-n METAL ASSEMBLY PASTE/SPRAY MOLYKOTE G-n PLUS PASTE MOLYKOTE G-RAPID PLUS PASTE/SPRAY MOLYKOTE 1000 PASTE MOLYKOTE M-77 PASTE MOLYKOTE P-37 PASTE MOLYKOTE P-40 PASTE MOLYKOTE P-74 PASTE MOLYKOTE P-1900 PASTE MOLYKOTE U-n PASTE *All values and calculations in this table were calculated by using the K-Factor formula and are based on a standard, 5/8 inch UNF fastener.

5 Torque Proper bolt torque is required to achieve appropriate bolt tension and elongation. Torque must overcome all sources of friction before elongation can occur. Thread and bolthead friction can be reduced and made consistent by adding a lubricant. Required torque calculations for proper bolt elongation are made based on threaded fastener geometry and friction of thread and load-bearing surfaces. The friction factor applied to torque calculations is referred to as K-Factor. Both thread and bolt-head friction coefficients are used to calculate K-Factor, so it is through lubrication that friction and K-Factor can be controlled to ensure proper bolt tension and elongation are achieved for a derived torque value. In assembly, the torque energy is first consumed by overcoming friction. The remaining energy is consumed by bolt elongation (which provides the clamping force). Without proper lubrication, too much torque is used to overcome friction, resulting in insufficient bolt elongation. K-FACTOR FORMULA K = root crest [ (0.5d p )(tan λ + µ t sec β) ] (1 - µ t tan λ sec β) D Where D = nominal bolt shank diameter β = thread half-angle = 60º/2 = 30º λ = thread helix angle = tan-1 (p/πd p ) ρ = pitch d p = bolt pitch diameter µ t = coefficient of thread friction µ c = coefficient of collar (head) friction α p pitch minor dia. pitch dia. depth + [0.625µ c ] major dia. thread angle Failure Mechanisms Defined Unequal coefficients of friction (µ) High µ of mating surfaces (head, nuts, shank and threads) can result in increased twisting of the fastener and reduced clamping force. Low µ of mating surfaces can result in excessive bolt elongation. Stick-slip The difference between static friction and kinetic friction when two surfaces are in contact. Stress corrosion cracking At high temperatures, sulfur diffuses into grain boundaries, producing high stress points. The sulfur then combines with nickel (of alloy steels) to form sulfide crystals. These crystals grow, increasing the stress and creating larger cracks. Fretting When vibration induces wear of oxide layers, the oxide particles clog internal clearances, leading to seizure. Galling During sliding contact, the oxide layer of threaded materials peels away. Asperities transfer from one part to the other, then break away, destroying the surface and preventing disassembly. Seizing Caused by fretting, oxide-free surfaces cold weld under extreme pressure, preventing disassembly.

6 L U B R I C A N T S A R E NOT CREATED EQUAL DIFFERENT BY DESIGN To ensure assembly and disassembly of threaded connections over time, the lubricant must stay in place, even under harsh environments. Molykote brand Anti-Seize Pastes and Anti-Friction Coatings offer long-term, effective solutions. These lubrication solutions form a protective layer between threaded surfaces, easing assembly and disassembly, while protecting against wear and corrosion that can lead to connection failure. Greases are designed to bleed base oils, which provide lubrication. But in threaded connections, the lubricant may not carry high load and the base oil will evaporate, reducing grease life. Anti-Seize Pastes contain a high concentration of solid lubricants for protecting industrial components from galling, fretting corrosion, stick slip, seizure or damage. They provide corrosion protection, water washout resistance and a consistent coefficient of friction. These solid lubricants remain in place even at high temperatures and under heavy loads to help with long-term lubrication. To ensure optimal performance of threaded connections, the appropriate Molykote Anti-Seize Paste needs to be selected for the application conditions. Anti-Friction Coatings are paint-like products that form a slippery film that covers and smoothes surface roughness. This optimizes friction control, even under extreme loads and working conditions. However, the effectiveness and surface life of an AFC is greatly affected by the surface pretreatment of the component, such as degreasing, phosphating, sandblasting and anodizing.

7 TYPICAL PROPERTIES OF SOLID LUBRICANTS USED IN ANTI-SEIZE PASTE AND ANTI-FRICTION COATING FORMULATIONS Anti-Seize Pastes Molykote brand Anti-Seize Pastes are highperformance products specially formulated for harsh conditions. Unlike conventional greases or compounds, Molykote Anti-Seize Pastes create and maintain a lubricating layer, despite extreme loads and temperatures. Molykote pastes provide: Wear protection Reliable performance across wide temperature ranges Consistent coefficient of friction (µ) Water washout resistance Corrosion protection Immediate lubrication once applied Long-term lubrication Easy, quick and accurate application of Anti-Seize Pastes can be achieved by brushing or dispensed pumping. Some Anti-Seize Pastes are also available in spray form. Anti-Friction Coatings Molykote brand Anti-Friction Coatings are very useful for parts exposed to dusty environments or inaccessible areas where long-term lubrication is desired. The parts can be pre-lubricated in a clean environment to reduce handling during field assembly operations. Molykote brand AFCs are formulated to offer these benefits after curing: Dry lubrication By combining different types of solid lubricants in paste formulations, we get increased protection from fretting corrosion, increased load-carrying and wear prevention. The sum of what they can do together is superior to what they offer separately. Coating that is nonflammable Graphite High temperature stability Good lubricant under humidity Low coefficient of friction at high loads Protects against fretting corrosion Molybdenum Disulfide (MoS 2 ) High load carrying capacity Wide temperature range Excellent adhesion Protects against fretting corrosion Friction decreases with increasing load Prevents stick-slip Not for use in humid environments Polytetrafluoroethylene (PTFE) Colorless Low load carrying capacity Low coefficient of friction at low loads Good chemical resistance Good at reducing sliding friction Copper High load carrying capacity High temperature stability Should not be used with stainless steel above temperatures of 1000 C (1832 F) May promote galvanic corrosion White Solids Protects against fretting corrosion Suitable for high temperatures Excellent adhesion Film that does not attract dirt and dust Additional corrosion protection Long-term lubrication without evaporation Effective lubrication even after prolonged service life Application methods include hand or drum spraying, dipping, centrifuging, brushing, roll coating or printing. The best application method is at the discretion of the end user and depends on the geometry of the part being coated.

8 Is dry lubrication needed? YES, my application is exposed to dust, dirt and debris and would benefit from dry lubrication. Choose Molykote brand Anti-Friction Coatings. NO: Choose Molykote brand Anti-Seize Pastes. Can your part be thoroughly cleaned and dried? YES: Choose Molykote Anti-Friction Coatings. NO: Consider Molykote Anti-Seize Pastes. SELECT THE RIGHT LUBRICANT The Molykote Anti-Seize Pastes and Molykote Anti-Friction Coatings (AFCs) presented in this brochure are specially formulated for use on threaded connections, helping deliver long-term protection, reliability and productivity. While Molykote Anti-Seize Pastes and Molykote AFCs offer many similar benefits, they perform best in specific applications: The performance of Molykote Anti-Seize Pastes does not require extensive surface preparation, so they are especially useful in the field. Molykote AFCs must be applied to surfaces that can be thoroughly cleaned and dried, and are often prepared in a clean environment as an engineered solution to help improve maintainability. When used together, Molykote Anti-Seize Pastes and AFCs can deliver synergistic performance. You can use the following tables to select the Molykote lubricant that best satisfies your needs. For more information and technical specifications or to contact a lubrication expert, visit molykote.com.

9 Molykote Brand Anti-Seize Pastes Selection Table Using Anti-Seize Pastes is one of the best ways to reduce and control friction in threaded connections, ensuring long-term performance and easy disassembly and reassembly. To determine the appropriate Anti-Seize Paste, consider the load, environment, temperature and speed of your application. Below is a general description of Molykote Anti-Seize Pastes that Dow Corning identifies as best suited for threaded connections. PRODUCT NAME KEY FEATURES TEMPERATURE RANGE C SOLID LUBRICANTS Capability Strong Adhesion Metal-Free Composition Galling Prevention Fretting Corrosion Protection Galling Prevention Fretting Corrosion Protection Water Resistance High Loading Carrying Capability High Loading Carrying Capability High Load Water Resistance Suitable for Low to Moderate Loads Suitable for Low to Moderate Loads Carrying Capability MOLYKOTE G-n METAL ASSEMBLY PASTE /SPRAY Suitable for general assembly and running-in Up to MoS 2, white solids MOLYKOTE G-n PLUS PASTE Copper-free Up to 400 MoS 2, graphite, white solids MOLYKOTE G-RAPID PLUS PASTE/SPRAY Provides consistently low coefficient of friction Up to 400 MoS 2, graphite, white solids MOLYKOTE 1000 PASTE Good for high load and vibration applications where there is a need to establish consistent torque -30 to 650 Copper and graphite, white solids MOLYKOTE M-77 PASTE Silicone base oil provides higher stability Stays paste-like at higher temperatures Compatible with many elastomers and plastics Up to MoS 2 MOLYKOTE P-37 PASTE High purity Suitable for stainless, austenite and high nickel chromium steel Prevents stress corrosion cracking and solder embrittlement -30 to Zirconium dioxide MOLYKOTE P-40 PASTE Metal-free Suitable for water contact -40 to White solids and PTFE MOLYKOTE P-74 PASTE Synthetic base oil carrier Remains grease-like for longer period of time -40 to 200 Graphite and white solids MOLYKOTE P-1900 PASTE Suitable for food processing machinery FDA 21 CFR NSF H1 Classification -30 to 300 White solids MOLYKOTE U-n PASTE Polyalkylene glycol (PAG) base oil Extremely tacky Compatible with natural rubber Up to MoS 2 and white solids 1 Temperature range of solid lubricants

10 Molykote Brand Anti-Friction Coatings (AFCs) Selection Table Using an AFC is one of the best ways to reduce and control friction in threaded connections, ensure long-term performance, and easy disassembly and reassembly. To determine the appropriate AFC, remember to consider service requirements, the desired coating method and the specific advantages for different applications. Below are general descriptions of Molykote AFCs that Dow Corning identifies as best suited for threaded connections. PRODUCT NAME KEY FEATURES TEMPERATURE RANGE C SOLID LUBRICANT/ BINDER High Load Carrying Chemical Resistance Fuel & Oil Resistance Fretting Corrosion Corrosion Resistance MOLYKOTE 3402-C ANTI-FRICTION COATING Room temperature curing High pressure and wear resistance -200 to 310 Solids: MoS 2 Binder: proprietary MOLYKOTE D-708 ANTI-FRICTION COATING Heat curing Black glossy finish -64 to 240 Solids: PTFE Binder: epoxy MOLYKOTE D-7409 ANTI-FRICTION COATING Heat curing Suitable for high temperatures -70 to 300 Solids: MoS 2 Binder: polyamide-imide MOLYKOTE 3400A ANTI-FRICTION COATING Heat curing Excellent adhesion -200 to 260 Solids: MoS 2 Binder: epoxy MOLYKOTE D-321 R ANTI-FRICTION COATING Room temperature curing Available as an aerosol spray -200 to 260 Solids: MoS 2, graphite Binder: titanate MOLYKOTE 106 ANTI-FRICTION COATING Heat curing Easy to apply -70 to 250 Solids: MoS 2 Binder: epoxy Need more information? Visit molykote.com or contact your Dow Corning Molykote lubricants distributor to get expert advice.

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12 Learn More Molykote lubricants are available through a distributor network of more than 3,000 distributors worldwide. And, Dow Corning has Lubricant Expertise Centers strategically located globally to provide you with expert technical service and support. In addition to Molykote Anti-Seize Pastes and Anti- Friction Coatings, our other Smart Lubrication solutions include multipurpose oils, synthetic and ultra-highpurity mineral oil fluids, specialty compounds, greases and more. Learn more now about our extensive product and service offering by visiting molykote.com or industrial@dowcorning.com. FPO Images: Page 1, AV20593, AV20600; Page 2, AV19522; Page 3, AV19512, AV19520, AV17005; Page 4, AV19519, AV19516; Page 5, AV19513; Page 6, AV19514, AV19524; Page 8, AV19521; Page 10, AV19523; Page 11, AV19515 LIMITED WARRANTY INFORMATION PLEASE READ CAREFULLY The information contained herein is offered in good faith and is believed to be accurate. However, because conditions and methods of use of our products are beyond our control, this information should not be used in substitution for customer s tests to ensure that our products are safe, effective and fully satisfactory for the intended end use. Suggestions of use shall not be taken as inducements to infringe any patent. Dow Corning s sole warranty is that our products will meet the sales specifications in effect at the time of shipment. Your exclusive remedy for breach of such warranty is limited to refund of purchase price or replacement of any product shown to be other than as warranted. DOW CORNING SPECIFICALLY DISCLAIMS ANY OTHER EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY. DOW CORNING DISCLAIMS LIABILITY FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES. Dow Corning is a registered trademark of Dow Corning Corporation. We help you invent the future is a trademark of Dow Corning Corporation. Molykote is a registered trademark of Dow Corning Corporation. Smart Lubrication is a trademark of Dow Corning Corporation. 2012, 2013 Dow Corning Corporation. All rights reserved. AMPM Form No B-01